From owner-svn-src-head@FreeBSD.ORG  Mon Mar  4 15:57:41 2013
Return-Path: <owner-svn-src-head@FreeBSD.ORG>
Delivered-To: svn-src-head@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id D5AA0CAE;
 Mon,  4 Mar 2013 15:57:41 +0000 (UTC)
 (envelope-from davide@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org
 [IPv6:2001:1900:2254:2068::e6a:0])
 by mx1.freebsd.org (Postfix) with ESMTP id A5B962DD;
 Mon,  4 Mar 2013 15:57:41 +0000 (UTC)
Received: from svn.freebsd.org ([127.0.1.70])
 by svn.freebsd.org (8.14.5/8.14.5) with ESMTP id r24FvfJD010387;
 Mon, 4 Mar 2013 15:57:41 GMT (envelope-from davide@svn.freebsd.org)
Received: (from davide@localhost)
 by svn.freebsd.org (8.14.6/8.14.5/Submit) id r24Fvfvx010386;
 Mon, 4 Mar 2013 15:57:41 GMT (envelope-from davide@svn.freebsd.org)
Message-Id: <201303041557.r24Fvfvx010386@svn.freebsd.org>
From: Davide Italiano <davide@FreeBSD.org>
Date: Mon, 4 Mar 2013 15:57:41 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: svn commit: r247797 - head/sys/kern
X-SVN-Group: head
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 04 Mar 2013 15:57:41 -0000

Author: davide
Date: Mon Mar  4 15:57:41 2013
New Revision: 247797
URL: http://svnweb.freebsd.org/changeset/base/247797

Log:
  MFcalloutng:
  kern_nanosleep() is now converted to use tsleep_sbt(). With this change
  nanosleep() and usleep() can handle sub-tick precision for timeouts.
  Also, try to help coalesce of events passing as argument to tsleep_bt()
  a precision value calculated as a percentage of the sleep time.
  This percentage is default 5%, but it can tuned according to users
  need via the sysctl interface.
  
  Sponsored by:	Google Summer of Code 2012, iXsystems inc.
  Tested by:	flo, marius, ian, markj, Fabian Keil

Modified:
  head/sys/kern/kern_time.c

Modified: head/sys/kern/kern_time.c
==============================================================================
--- head/sys/kern/kern_time.c	Mon Mar  4 15:34:59 2013	(r247796)
+++ head/sys/kern/kern_time.c	Mon Mar  4 15:57:41 2013	(r247797)
@@ -43,6 +43,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/resourcevar.h>
 #include <sys/signalvar.h>
 #include <sys/kernel.h>
+#include <sys/sleepqueue.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysctl.h>
 #include <sys/sysent.h>
@@ -481,38 +482,37 @@ static int nanowait;
 int
 kern_nanosleep(struct thread *td, struct timespec *rqt, struct timespec *rmt)
 {
-	struct timespec ts, ts2, ts3;
-	struct timeval tv;
+	struct timespec ts;
+	sbintime_t sbt, sbtt, prec, tmp;
 	int error;
 
 	if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
 		return (EINVAL);
 	if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
 		return (0);
-	getnanouptime(&ts);
-	timespecadd(&ts, rqt);
-	TIMESPEC_TO_TIMEVAL(&tv, rqt);
-	for (;;) {
-		error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp",
-		    tvtohz(&tv));
-		getnanouptime(&ts2);
-		if (error != EWOULDBLOCK) {
-			if (error == ERESTART)
-				error = EINTR;
-			if (rmt != NULL) {
-				timespecsub(&ts, &ts2);
-				if (ts.tv_sec < 0)
-					timespecclear(&ts);
-				*rmt = ts;
-			}
-			return (error);
+	tmp = tstosbt(*rqt);
+	prec = tmp;
+	prec >>= tc_precexp;
+	if (TIMESEL(&sbt, tmp))
+		sbt += tc_tick_sbt;
+	sbt += tmp;
+	error = tsleep_sbt(&nanowait, PWAIT | PCATCH, "nanslp", sbt, prec,
+	    C_ABSOLUTE);
+	if (error != EWOULDBLOCK) {
+		if (error == ERESTART)
+			error = EINTR;
+		TIMESEL(&sbtt, tmp);
+		if (rmt != NULL) {
+			ts = sbttots(sbt - sbtt);
+			if (ts.tv_sec < 0)
+				timespecclear(&ts);
+			*rmt = ts;
 		}
-		if (timespeccmp(&ts2, &ts, >=))
+		if (sbtt >= sbt)
 			return (0);
-		ts3 = ts;
-		timespecsub(&ts3, &ts2);
-		TIMESPEC_TO_TIMEVAL(&tv, &ts3);
+		return (error);
 	}
+	return (0);
 }
 
 #ifndef _SYS_SYSPROTO_H_